/* * drm gem CMA (contiguous memory allocator) helper functions * * Copyright (C) 2012 Sascha Hauer, Pengutronix * * Based on Samsung Exynos code * * Copyright (c) 2011 Samsung Electronics Co., Ltd. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include #include #include #include #include #include #include #include #include /** * DOC: cma helpers * * The Contiguous Memory Allocator reserves a pool of memory at early boot * that is used to service requests for large blocks of contiguous memory. * * The DRM GEM/CMA helpers use this allocator as a means to provide buffer * objects that are physically contiguous in memory. This is useful for * display drivers that are unable to map scattered buffers via an IOMMU. */ /** * __drm_gem_cma_create - Create a GEM CMA object without allocating memory * @drm: DRM device * @size: size of the object to allocate * * This function creates and initializes a GEM CMA object of the given size, * but doesn't allocate any memory to back the object. * * Returns: * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative * error code on failure. */ static struct drm_gem_cma_object * __drm_gem_cma_create(struct drm_device *drm, size_t size) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *gem_obj; int ret; cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL); if (!cma_obj) return ERR_PTR(-ENOMEM); gem_obj = &cma_obj->base; ret = drm_gem_object_init(drm, gem_obj, size); if (ret) goto error; ret = drm_gem_create_mmap_offset(gem_obj); if (ret) { drm_gem_object_release(gem_obj); goto error; } return cma_obj; error: kfree(cma_obj); return ERR_PTR(ret); } /** * drm_gem_cma_create - allocate an object with the given size * @drm: DRM device * @size: size of the object to allocate * * This function creates a CMA GEM object and allocates a contiguous chunk of * memory as backing store. The backing memory has the writecombine attribute * set. * * Returns: * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative * error code on failure. */ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm, size_t size) { struct drm_gem_cma_object *cma_obj; int ret; size = round_up(size, PAGE_SIZE); cma_obj = __drm_gem_cma_create(drm, size); if (IS_ERR(cma_obj)) return cma_obj; cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size, &cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN); if (!cma_obj->vaddr) { dev_err(drm->dev, "failed to allocate buffer with size %zu\n", size); ret = -ENOMEM; goto error; } return cma_obj; error: drm_gem_cma_free_object(&cma_obj->base); return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(drm_gem_cma_create); /** * drm_gem_cma_create_with_handle - allocate an object with the given size and * return a GEM handle to it * @file_priv: DRM file-private structure to register the handle for * @drm: DRM device * @size: size of the object to allocate * @handle: return location for the GEM handle * * This function creates a CMA GEM object, allocating a physically contiguous * chunk of memory as backing store. The GEM object is then added to the list * of object associated with the given file and a handle to it is returned. * * Returns: * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative * error code on failure. */ static struct drm_gem_cma_object * drm_gem_cma_create_with_handle(struct drm_file *file_priv, struct drm_device *drm, size_t size, uint32_t *handle) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *gem_obj; int ret; cma_obj = drm_gem_cma_create(drm, size); if (IS_ERR(cma_obj)) return cma_obj; gem_obj = &cma_obj->base; /* * allocate a id of idr table where the obj is registered * and handle has the id what user can see. */ ret = drm_gem_handle_create(file_priv, gem_obj, handle); if (ret) goto err_handle_create; /* drop reference from allocate - handle holds it now. */ drm_gem_object_unreference_unlocked(gem_obj); return cma_obj; err_handle_create: drm_gem_cma_free_object(gem_obj); return ERR_PTR(ret); } /** * drm_gem_cma_free_object - free resources associated with a CMA GEM object * @gem_obj: GEM object to free * * This function frees the backing memory of the CMA GEM object, cleans up the * GEM object state and frees the memory used to store the object itself. * Drivers using the CMA helpers should set this as their DRM driver's * ->gem_free_object() callback. */ void drm_gem_cma_free_object(struct drm_gem_object *gem_obj) { struct drm_gem_cma_object *cma_obj; cma_obj = to_drm_gem_cma_obj(gem_obj); if (cma_obj->vaddr) { dma_free_writecombine(gem_obj->dev->dev, cma_obj->base.size, cma_obj->vaddr, cma_obj->paddr); } else if (gem_obj->import_attach) { drm_prime_gem_destroy(gem_obj, cma_obj->sgt); } drm_gem_object_release(gem_obj); kfree(cma_obj); } EXPORT_SYMBOL_GPL(drm_gem_cma_free_object); /** * drm_gem_cma_dumb_create_internal - create a dumb buffer object * @file_priv: DRM file-private structure to create the dumb buffer for * @drm: DRM device * @args: IOCTL data * * This aligns the pitch and size arguments to the minimum required. This is * an internal helper that can be wrapped by a driver to account for hardware * with more specific alignment requirements. It should not be used directly * as the ->dumb_create() callback in a DRM driver. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv, struct drm_device *drm, struct drm_mode_create_dumb *args) { unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8); struct drm_gem_cma_object *cma_obj; if (args->pitch < min_pitch) args->pitch = min_pitch; if (args->size < args->pitch * args->height) args->size = args->pitch * args->height; cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size, &args->handle); return PTR_ERR_OR_ZERO(cma_obj); } EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create_internal); /** * drm_gem_cma_dumb_create - create a dumb buffer object * @file_priv: DRM file-private structure to create the dumb buffer for * @drm: DRM device * @args: IOCTL data * * This function computes the pitch of the dumb buffer and rounds it up to an * integer number of bytes per pixel. Drivers for hardware that doesn't have * any additional restrictions on the pitch can directly use this function as * their ->dumb_create() callback. * * For hardware with additional restrictions, drivers can adjust the fields * set up by userspace and pass the IOCTL data along to the * drm_gem_cma_dumb_create_internal() function. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_cma_dumb_create(struct drm_file *file_priv, struct drm_device *drm, struct drm_mode_create_dumb *args) { struct drm_gem_cma_object *cma_obj; args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8); args->size = args->pitch * args->height; cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size, &args->handle); return PTR_ERR_OR_ZERO(cma_obj); } EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create); /** * drm_gem_cma_dumb_map_offset - return the fake mmap offset for a CMA GEM * object * @file_priv: DRM file-private structure containing the GEM object * @drm: DRM device * @handle: GEM object handle * @offset: return location for the fake mmap offset * * This function look up an object by its handle and returns the fake mmap * offset associated with it. Drivers using the CMA helpers should set this * as their DRM driver's ->dumb_map_offset() callback. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv, struct drm_device *drm, u32 handle, u64 *offset) { struct drm_gem_object *gem_obj; mutex_lock(&drm->struct_mutex); gem_obj = drm_gem_object_lookup(drm, file_priv, handle); if (!gem_obj) { dev_err(drm->dev, "failed to lookup GEM object\n"); mutex_unlock(&drm->struct_mutex); return -EINVAL; } *offset = drm_vma_node_offset_addr(&gem_obj->vma_node); drm_gem_object_unreference(gem_obj); mutex_unlock(&drm->struct_mutex); return 0; } EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset); const struct vm_operations_struct drm_gem_cma_vm_ops = { .open = drm_gem_vm_open, .close = drm_gem_vm_close, }; EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops); static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj, struct vm_area_struct *vma) { int ret; /* * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map * the whole buffer. */ vma->vm_flags &= ~VM_PFNMAP; vma->vm_pgoff = 0; ret = dma_mmap_writecombine(cma_obj->base.dev->dev, vma, cma_obj->vaddr, cma_obj->paddr, vma->vm_end - vma->vm_start); if (ret) drm_gem_vm_close(vma); return ret; } /** * drm_gem_cma_mmap - memory-map a CMA GEM object * @filp: file object * @vma: VMA for the area to be mapped * * This function implements an augmented version of the GEM DRM file mmap * operation for CMA objects: In addition to the usual GEM VMA setup it * immediately faults in the entire object instead of using on-demaind * faulting. Drivers which employ the CMA helpers should use this function * as their ->mmap() handler in the DRM device file's file_operations * structure. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *gem_obj; int ret; ret = drm_gem_mmap(filp, vma); if (ret) return ret; gem_obj = vma->vm_private_data; cma_obj = to_drm_gem_cma_obj(gem_obj); return drm_gem_cma_mmap_obj(cma_obj, vma); } EXPORT_SYMBOL_GPL(drm_gem_cma_mmap); #ifdef CONFIG_DEBUG_FS /** * drm_gem_cma_describe - describe a CMA GEM object for debugfs * @cma_obj: CMA GEM object * @m: debugfs file handle * * This function can be used to dump a human-readable representation of the * CMA GEM object into a synthetic file. */ void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj, struct seq_file *m) { struct drm_gem_object *obj = &cma_obj->base; struct drm_device *dev = obj->dev; uint64_t off; WARN_ON(!mutex_is_locked(&dev->struct_mutex)); off = drm_vma_node_start(&obj->vma_node); seq_printf(m, "%2d (%2d) %08llx %pad %p %zu", obj->name, obj->refcount.refcount.counter, off, &cma_obj->paddr, cma_obj->vaddr, obj->size); seq_printf(m, "\n"); } EXPORT_SYMBOL_GPL(drm_gem_cma_describe); #endif /** * drm_gem_cma_prime_get_sg_table - provide a scatter/gather table of pinned * pages for a CMA GEM object * @obj: GEM object * * This function exports a scatter/gather table suitable for PRIME usage by * calling the standard DMA mapping API. Drivers using the CMA helpers should * set this as their DRM driver's ->gem_prime_get_sg_table() callback. * * Returns: * A pointer to the scatter/gather table of pinned pages or NULL on failure. */ struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj) { struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj); struct sg_table *sgt; int ret; sgt = kzalloc(sizeof(*sgt), GFP_KERNEL); if (!sgt) return NULL; ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr, cma_obj->paddr, obj->size); if (ret < 0) goto out; return sgt; out: kfree(sgt); return NULL; } EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table); /** * drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another * driver's scatter/gather table of pinned pages * @dev: device to import into * @attach: DMA-BUF attachment * @sgt: scatter/gather table of pinned pages * * This function imports a scatter/gather table exported via DMA-BUF by * another driver. Imported buffers must be physically contiguous in memory * (i.e. the scatter/gather table must contain a single entry). Drivers that * use the CMA helpers should set this as their DRM driver's * ->gem_prime_import_sg_table() callback. * * Returns: * A pointer to a newly created GEM object or an ERR_PTR-encoded negative * error code on failure. */ struct drm_gem_object * drm_gem_cma_prime_import_sg_table(struct drm_device *dev, struct dma_buf_attachment *attach, struct sg_table *sgt) { struct drm_gem_cma_object *cma_obj; if (sgt->nents != 1) return ERR_PTR(-EINVAL); /* Create a CMA GEM buffer. */ cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size); if (IS_ERR(cma_obj)) return ERR_CAST(cma_obj); cma_obj->paddr = sg_dma_address(sgt->sgl); cma_obj->sgt = sgt; DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size); return &cma_obj->base; } EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table); /** * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object * @obj: GEM object * @vma: VMA for the area to be mapped * * This function maps a buffer imported via DRM PRIME into a userspace * process's address space. Drivers that use the CMA helpers should set this * as their DRM driver's ->gem_prime_mmap() callback. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_cma_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma) { struct drm_gem_cma_object *cma_obj; struct drm_device *dev = obj->dev; int ret; mutex_lock(&dev->struct_mutex); ret = drm_gem_mmap_obj(obj, obj->size, vma); mutex_unlock(&dev->struct_mutex); if (ret < 0) return ret; cma_obj = to_drm_gem_cma_obj(obj); return drm_gem_cma_mmap_obj(cma_obj, vma); } EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap); /** * drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual * address space * @obj: GEM object * * This function maps a buffer exported via DRM PRIME into the kernel's * virtual address space. Since the CMA buffers are already mapped into the * kernel virtual address space this simply returns the cached virtual * address. Drivers using the CMA helpers should set this as their DRM * driver's ->gem_prime_vmap() callback. * * Returns: * The kernel virtual address of the CMA GEM object's backing store. */ void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj) { struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj); return cma_obj->vaddr; } EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap); /** * drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual * address space * @obj: GEM object * @vaddr: kernel virtual address where the CMA GEM object was mapped * * This function removes a buffer exported via DRM PRIME from the kernel's * virtual address space. This is a no-op because CMA buffers cannot be * unmapped from kernel space. Drivers using the CMA helpers should set this * as their DRM driver's ->gem_prime_vunmap() callback. */ void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr) { /* Nothing to do */ } EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);